What's really incredible is a new feature for the iMacs 27" models that allows them to act as external monitors or HDTVs. You'll be able to attach DVD players, Blu-Ray players, gaming consoles, or even other computers, and display them on the bright, clear, iMac display. Update: The 27" will handle DisplayPort-based input, with adapters to be announced. The 21.5" model will not support video input, based on the spec page.